Steel SUH660-HR vs SUH660-ST
Steel · SUH660 temper comparison
SUH660-HR and SUH660-ST are two conditions of the same steel grade, SUH660: HR (hot rolled) versus ST (solution annealed). The chemistry is identical, so every difference below comes from the condition. SUH660-HR is the stronger of the two: yield strength 420 MPa (60.9 ksi) against 285 MPa (41.3 ksi) for SUH660-ST, about 47% more; tensile strength follows at 800 MPa (116 ksi) vs 655 MPa (95 ksi). In exchange, SUH660-ST is the more ductile: elongation 45% versus 30% for SUH660-HR, and SUH660-HR is harder (230 HB vs 190 HB). SUH660-ST runs hotter in service (600°C vs 550°C continuous).
SUH660-HRChoose it when strength drives the design.
SUH660-STChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
SUH660-HR vs SUH660-ST: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all steel grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell C
Hardness, Vickers
Same in both: Shear Modulus 77 GPa11.2 Msi · Bulk Modulus 176 GPa25.5 Msi · Poisson's Ratio 0.31
Physical
Density and transition temperatures.
Same in both: Density 7.94 g/cm³0.29 lb/in³ · Melting Point (Solidus) 1,370°C2,498 °F · Liquidus Temperature 1,400°C2,552 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Max Service Temperature (continuous)
Same in both: Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 16.4 µm/m·K9.1 µin/in·°F · Latent Heat of Fusion 285 J/g123 BTU/lb · Min Service Temperature -196°C-321 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.1 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Formability (cold)
Same in both: Weldability 65 / 100 · Brazeability / Solderability 60 / 100 · Polishability 75 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 90 MJ/kg38,693 BTU/lb · Embodied Carbon (primary production) 6.5 kg CO₂/kg · Embodied Water 220 L/kg26.4 gal/lb · Typical Recycled Content 30%
Strength versus weight
Yield strength against density for every steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
SUH660-HR vs SUH660-ST — frequently asked
Is SUH660-HR stronger than SUH660-ST?
Yes. SUH660-HR has a typical yield strength of 420 MPa (60.9 ksi) against 285 MPa (41.3 ksi) for SUH660-ST — about 47% more. Tensile strength is 800 MPa (116 ksi) vs 655 MPa (95 ksi).
Which condition does FabDigit quote by default, HR or ST?
STA is the default SUH660 condition in the FabDigit quote flow (neither HR nor ST). The other condition is available on request or by drawing note — specify it in the material field or the part notes and the quote is priced for it.
Which is easier to machine, SUH660-HR or SUH660-ST?
SUH660-ST, by a small margin. Both rate poor for machinability — 30/100 against 25/100 for SUH660-HR.
Ready to make it?
Upload a CAD file and FabDigit prices the part in SUH660-HR and SUH660-ST side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.
Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.